Perpetual calendar.



D. SFROWE. PERPETUAL CALENDAR. APPLICATION nun In 5; 190a.

Patented Mar. 16, 1909.

PV/TNESSES: [/WE/vm/e fifl'rl'd A5 0176.

' I Alfarn y UNITED STATES PATENT OFFICE.

DAVID S. ROWE, OF CHICAGO, ILLINOIS.

PERPETUAL CALENDAR.

To all whom it may concern:

Be it known that I, DAVID S. ROWE, citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Perpetual Calendars, of which the following is a specification.

This invention is a perpetual calendar, and consists of a set of disks pivoted together, one disk having thereon a table of the months and centuries, another disk having thereon a table of the days of the month, and a third disk having thereon the days of the week as well as a table of the individual years for each century. The tables are so arranged that they may be brought into line radially, by turning the disks to designate the desired ear.

3 The invention is illustrated in the accompanying drawings, in which Figure 1 is a plan view of the device and Fig. 2 is a central cross section thereof.

The largest or primary disk is indicated at 6. This has thereon a table of months 7, as well as a table of centuries indicated at 8 ar ranged in four rows or lines, and the respec tive lines indicate the correct position of the secondary disk with respect to all dates in the centuries indicated by the numbers adjacent said lines. It will be understood that these numbers refer to the centuries as such, that is, the 12th, 16th, 20th centuries, etc. The second disk is indicated at 9 and has at one side a segmental part which contains the days of the month arranged in radial rows, as indicated at 10. The third disk, 11, contains marks of the days of the week around the edge thereof, as indicated at 12. These names are arranged in succession, and in radial spaces corresponding to the monthly table 10. This disk also contains a table of individual years indicated at 13, arranged in radial lines, in succession, corresponding to the lines of the days of the week, and the series of the numbers of the years is interrupted at proper intervals according to leap years, forming leap year spaces which are indicated by a cross, as at 14.

It may be here remarked that the device shown has five disks, the second and third disks being duplicated on opposite sides of the primary disk 6. The purpose of this is Specification of Letters Patent.

Application filed May 5, 1908.

Patented March 16, 1909.

Serial No. 430,963.

simply to accommodate the requisite number of years within the compass of a device small enough to be carried in the pocket, without having the numbers thereon so small as not to be easily read. Consequently the disk 11 on one side contains the year numbers running from 0 to 50, and the disk 11 on the opposite side contains the year numbers running from 51 to 99. Otherwise the disks are identical. Obviously by making disk number 11 on one side large enough, the whole century of years could be placed thereon, but the device may be made smaller, and the numbers larger, by the duplication of the disks 9 and 11 on opposite sides of the disk 6. The disks are fastened at the center by a pivot screw 15.

In the use of the device, the disk 9 is turned until the edge of the segment containing the table 10 is in line with one of the lines of centuries 8, according to the century for which the calendar is to be set. Thus, for the 19th century the segment is set at the first line, as shown. Then the disk 11 is turned until the desired year, as indicated on the table 13, is in line with the desired month indicated on the table 7. Then it will be found that the table 12 of the days of the week will be properly set for the days of the month on the table 10, and will indicate or form a calendar for that month. By a proper manipulation of the disks any date may be ascertained or a calendar for any month produced.

I claim-- A perpetual calendar comprising a set of DAVID S. ROWE.

Witnesses:

NELLIE FELTsKoe, H. G. BATCHELOR. 

